10 Studies on Love, Friendship, and the Great Blurry Middle
Wednesday, October 22, 2025.
We pretend that romance and friendship are two different games: one played with candlelight, the other with take-out containers.
One gets poems, the other gets memes. But decades of research suggest that the border between them is porous — maybe even imaginary.
When you look closely, the emotional scaffolding of a deep friendship and that of a long-term romance are almost identical: mutual vulnerability, consistent responsiveness, trust, admiration, and shared humor.
The main difference, as John M. Gottman would say, is that romance adds sexual exclusivity and ritualized significance — not a separate emotional species, just a new tax bracket.
Let’s tour ten studies that expose the cultural illusion of difference, with commentary from some of psychology’s most enduring thinkers.
1. The Friends-to-Lovers Trajectory
Stinson, D. A. (2021). The friends-to-lovers pathway to romance.
Nearly two-thirds of romantic relationships begin as friendships. Love often sneaks in through the side door.
Gottman, whose longitudinal studies of couples are the gold standard of relational science, argues that “friendship is the foundation of lasting love.” The healthiest marriages, he says, look suspiciously like elaborate friendships with paperwork.
2. Shared Predictors of Satisfaction
Näslund & Reinholdsson (2016). Relationship satisfaction in friendships and romantic relationships.
The same variables predict happiness in both friendships and marriages: communication, trust, emotional attunement. In therapy, when I’m helping couples reconnect, we’re not “rebuilding passion.” We’re re-establishing friendship.
Psychologist Robert Sternberg called it the Triangular Theory of Love: intimacy, passion, commitment. Friendship supplies the first and often the last.
3. Affectional Parity
Meier et al. (2024). Unraveling the experience of affection across marital and friendship interactions.
Videotaped interactions showed that friends and spouses display nearly identical levels of affectionate behavior — touch, laughter, eye contact — when things are going well.
As Helen Fisher demonstrated in her neuroimaging work, both friendship and romance activate the same reward systems. The difference between “platonic warmth” and “romantic passion” is mostly dosage.
Biologically speaking, affection is our nervous system’s language for safety, not a declaration of ownership.
4. The Intimacy Continuum
Guinsburg found that emotional closeness exists on a continuum. The boundary between “just friends” and “in love” is social, not structural.
Cultural critic bell hooks made the same point in All About Love: “Rarely, if ever, are any of us taught that friendship itself is the practice of love.”
When friendship is devalued, romance collapses under the weight of impossible expectations.
5. The Self-Expansion Principle
Aron & Aron (1996). Self and self-expansion in relationships.
The Arons proposed that we fall in love with people who expand our sense of self. Whether it’s a spouse or a best friend, closeness functions as psychological scaffolding for growth.
Esther Perel modernized the idea: “Love rests on having; desire on wanting. Friendship offers safety; desire needs distance.”
In other words, safety and excitement are not enemies — they’re phases of the same relational metabolism.
6. Cognitive Interdependence Beyond Romance
Agnew et al. (1998). Cognitive interdependence.
Agnew called it “cognitive interdependence” — when “I” becomes “we.” His findings show the same mental merging in friendships that last for decades.
Gottman names this shared meaning: a private culture built from shorthand jokes, rituals, and emotional language. Whether you call it marriage or best-friendship, it’s the same exact neurological architecture.
7. Oxytocin Without the Romance
Taylor et al. (2000). Tend-and-befriend: A biobehavioral response to stress.
Taylor’s team showed that oxytocin — the “bonding hormone” — drives stress regulation in social connection, whether that connection is romantic or friendly.
If the human experiment had an all-purpose manifesto, it would be this: pair-bond for survival, friend-bond for civilization.
8. Friendship and Well-Being
Demir & Özdemir (2010). Friendship, need satisfaction, and happiness.
Friendship fulfills the same psychological needs outlined in self-determination theory: autonomy, competence, relatedness.
American culture tends to glorify the notion of “soulmates,” this study is quietly revolutionary. A friend who knows your grocery list may be doing more for your nervous system than your “twin flame.”
9. Passionate and Companionate Overlap
Sprecher & Regan (2002). Partner preferences in romantic and friendship contexts.
Participants ranked humor, warmth, reliability, and kindness as equally desirable in both friends and romantic partners.
Philosopher Alain de Botton once wrote that romance is “friendship with sexual exclusivity and a script.” Most of us are merely performing a narrower version of what friendship already makes possible.
10. The Fluidity Thesis
Their interviews reveal the tension between experience and social expectation. Participants often defined “romance” according to cultural norms — even when their actual relationships contradicted those norms.
So it seems that many of us still use the same outdated vocabulary to describe a far more fluid world of attachment.
The Takeaway
Across half a century of research, one theme repeats: friendship and romance share the same emotional grammar.
The difference lies in ritual — labels, exclusivity, sexual permission — not in empathy, care, or shared meaning.
That’s why therapy rooms fill with phrases like “We’re just friends” or “We never had sex, but it felt like a marriage.”
These aren’t contradictions. They’re coordinates from the borderlands of our definitions.
Love, friendship, partnership — these are adaptive states of intimacy, constrained by language but lived in gradients. The science has known this for decades. Culture is simply catching up.
If this resonates...
Many couples I work with discover that what’s missing isn’t “romance” — it’s the friendship underneath it.
If you’re ready and committed to rebuild that foundation — curiosity, humor, affection, and shared meaning — you can reach me here.
Because good therapy doesn’t just revive romance. It restores friendship — the quiet, enduring form of love that can hold everything else together.
Be Well, Stay Kind, and Godspeed.
REFERENCES:
Agnew, C. R., Van Lange, P. A. M., Rusbult, C. E., & Langston, C. A. (1998). Cognitive interdependence: Commitment and the mental representation of close relationships. Journal of Personality and Social Psychology, 74(4), 939–954.
Aron, A., & Aron, E. N. (1996). Self and self-expansion in relationships. In G. J. O. Fletcher & J. Fitness (Eds.), Knowledge structures in close relationships (pp. 325–344). Lawrence Erlbaum.
de Barros, A. C., Lackie, E. R. L., & van Anders, S. M. (2025). Sex, attraction, and social norms: Distinguishing romantic and non-romantic relationships in non-sexual contexts. Archives of Sexual Behavior.
Demir, M., & Özdemir, M. (2010). Friendship, need satisfaction, and happiness. Journal of Happiness Studies, 11(2), 243–259.
Guinsburg, A. S. (1973). An investigation of the components of platonic and romantic heterosexual relationships.Doctoral dissertation, University of North Dakota.
Meier, E. A., et al. (2024). Unraveling the experience of affection across marital and friendship interactions. Journal of Social and Personal Relationships, 41(9), 2345–2364.
Näslund, E., & Reinholdsson, K. (2016). Relationship satisfaction in friendships and romantic relationships: The role of communication, trust, and closeness. Linnaeus University Studies in Psychology.
Sprecher, S., & Regan, P. C. (2002). Liking some things (in some people) more than others: Partner preferences in romantic and friendship contexts. Journal of Social and Personal Relationships, 19(4), 463–481.*
Stinson, D. A. (2021). The friends-to-lovers pathway to romance: Prevalent, preferred, and overlooked. Social Psychological and Personality Science, 12(6), 1035–1045.
Taylor, S. E., Klein, L. C., Lewis, B. P., Gruenewald, T. L., Gurung, R. A. R., & Updegraff, J. A. (2000). Biobehavioral responses to stress in females: Tend-and-befriend, not fight-or-flight. Psychological Review, 107(3), 411–429.*